I have an 11x65 cell array. If I open it in variable window, only 16 of the 65 columns are displayed. I found no option to change max number of cols. I found the problem in 2015a and 2016a. In 2012b, however, all 65 columns are shown. The problem does not occur with structs.
EDIT: Things are starting to get creepy: Today a big array (40000x65) first showed 24 columns, and then all the other columns as well. I don't know how to reproduce when it works and when it does not. Today, 2 large tables were also open in the variable window. Perhaps that's the motivation for MATLAB to also show the ramaining cell columns. Or maybe there is a connection to free RAM?